Process and apparatus for volatilizing metal



H. E. BAKKEN PROCESS AND APPARATUS FOR VOLATILIZING METAL May l11 1926.

Y Filed April 27. 1921 lvlllllA/lllllllf oxide. The bath is of such a specific gravity Patented May 1l, 1926.

UNrrsD STATES PATENT OFFICE.

HERMAN E. BAKKEN, 0F NIAGARA FALLS, NEW YORK, ASSIGNOR TO AMERICAN MAG- NESIUM CORPORATION, OF NIAGARA FALLS, NEW YORK, A CORPORATION OF NEW YORK.

PROCESS AND AIPARATUS FOR VOLATILIZING METAL.

Application tiled April 27, 1921.

My invention relates to a process and apparatus for volatilizing metal from fused metalliferous material and particularly to the electrolytic production of magnesium from its fused salts, and one of the objects of the invention is to electrolytically decompose the metallic salts and collect the metal 'therefrom ultimately in the form of a pure distillate. Altho particularly adapted for magnesium, the .invention is equally applicable tb the other metals which have similar characteristics.

The application of my invention is illustrated herein, in connection with the oxide process of producing magnesium as disclosed in the patents to Seward 1,210,449, and 1,310,450 granted July 22, 1919. In those patents, there is disclosed a method of producing magnesium, comprising .the yelectrolysisof a molten bath of mixed fluorids, includmg magnesium iiuorid, and magnesium that it will support on its surface a crust of magnesium oxide and any separated meta] will rise to the topof the bath and collect beneath the said crust. The metal is intermittently removed by punching a hole in the crust and ladling it out by hand. The disadvantages of this method are that the metal contains undesirable impurities such as silicon and to secure pure metal must be reiined by a separate operation; also the temperature at which the bath is operated may be so high as to cause loss of metal by evaporation.

In the drawing Fig. 1 is a sectional elevation of the apparatus used in carrying out my invention, and

Fig. 2 is a section on the `line 2-2 of Fig. 1.

Referring to the drawing, 10 is a tank for holding the fused bath material and having anodes 11 along the median line thereof and cathodes 12 on both sides of the anodes. The metallic magnesium separates at the cathodes and being lighter than the bath material has a tendency to rise to the top of the bath. 4

Suspended directly over ,each cathode is an elongated bell or box 13 only one of which is shown, which may ,be completely submerged in the molten bath. Rising from its centre oint is a conduit-14 which extends upwar a suitable distance.- At its upper serial No. 464,823. f

container 17 are connected by a pipe 19 and also by a pipe line 20 containing valves 21. The pipe line 20 is adapted to be connected at 22 with-a vacuum pump for creating a vacuum in the entire system. For maintaining the desired temperature of this system any suitable means may be used, but I prefer to use electrical heating means.

The operation of my invention is as follows: When a vacuum is established in the conduit14, the result will be that the bath material will rise therein.l The height of the column of bath will depend on the amount of the vacuum and the specific gravity of the bath material, Any globules of metal separated at the cathode, on account of their specific gravity being lower than the` bath material, will rise to the surface and,

collect under the bell 13 and from there rise thro the bath material in the conduit 14. Due to the decreased pressure on the-column of bath material, the boiling point of the molten metal, within the iniuence'of the decreased pressure, will be lowered. The

metal which has separated in a liquid form at the temperature of the bath and at atmospheric pressure, will, by the time it has reached the top of the column` be transformed into metallic vapor, which will pass over and be condensed in the condenser 16. The metal in' the condenser 16 will remain liquid butl that in the pipe 19 Will solidify.

By intermittently thawing out the pipe 19,

`which may be heated by any suitable means, then closing the vacuum line to the condenslytic production of magnesium from its fused salts, and as anexempliiication, axprocess 1n which magnesium rises to the surface of the molten bath, it is noi intended to so limit its use. For instance there may be other metalliferous material than that specified to which the invention might be applied, and the metal may be plated out on to a molten cathode at the bottom of the bath and subsequently separated therefrom by distillation. While I have illustrated and described the preferred embodiment of the inlvention, it will lbe understood that I reserve the right to all changes properly falling within the scope and spirit of the appended claims.

Tclaim: l.

1. The process of reducing magnesium from its fused salts comprising subjecting the fused salts to electrolysis and simultaneously volatilizing the separated magnesium at; less than atmospheric ressure.

2. The process of reducing ma esium from its compounds comprising su jecting a bath of the fused compounds to electrolysis, the specific gravity of the bath being sufficiently high to cause the separated magnesium to rise to the surface 0f the bath, reducing the pressure to promote volatilization of and thereafter condensing the metallic vapor. Y

3. The process of reducing magnesium from its compounds comprising subjecting fused metalliferous material to electrolysis, a portion of fused material being at atmospheric pressure and another portion being at less than atmospheric pressure.

4. The process of reducing magnesium from its compounds comprising subjecting fused metalliferous material to electrolysis and causing a portion of fused magnesium containing material to take a position where it is subjected to less pressure than the main body thereof and maintaining such temperatures and pressures so that the separated metal will remain liquid in the main body thereof and vaporize in the said portion.

5. The process of reducing ma esium from its compounds comprising suljlecting fused metalliferous material to electrolysis, causing a portion of fused magnesium containing material to take a position where it may be subjected to lepressure than the main body thereof, maintaining such a temperature in the main body so that the separated metal will remain liquid therein, maintainingr substantiall the same temperature in the said ortion'as in the main ody, but reducing t e pressure thereon in order to promote volatihzation of the metal therein.

6. A process of reducing ma esium from its com ounds comprising su jecting fused metalli erous material to electrolysis, said material comprising magnesium oxide and magnesium fluorid, and causing a portion of fused magnesium containing material to take a position where it is subjected to less pressure than the main body thereof and maintaining such temperature and pressure that the separated metal will remain liquid in the main body thereof and vaporize in the said ortion.

7. The process o reducing magnesium Yfrom its compounds comprising subjecting fused metalliferous material to electrolysis, causing a portion of the fused magnesium containing material to take a position where it is subjected to less pressure thanV the main body thereof, the specific gravity of the bath being suhciently high to cause the separated magnesium to rise therein and maintaining such temperature and pressure that the separated metal will remain liquid in the main body thereof and vaporize in the said portion.

8. The process of Volatilizing metal from fused metalliferous material comprising subjecting a portion of the said material to such temperature and pressure so that the contained metal will not substantially volatilize and subjecting another portion to such temperature and pressure, so that the contained metal will volatilize.

9. The process of volatilizing metal from fused metalliferous material comprising causing a portion of fused material to take a position away from the main body, subjecting the main body of the material to atmospheric pressure and to such temperature so that it will not substantially volatilize and subjecting the said portion to less than atmospheric pressure and such temperature, so that the contained metal will volatilize. Y

10. An apparatus of the characterdescribed, comprising a receptacle for holding fused metalliferous material, a conduit combined with the receptacle and adapted to contain fused material, a condenser for metallic vapor, means fpr maintaining a vac; uum in the conduit to cause fused material to rise therein and metal to volatilize, the length of the conduit being greater than the height of the column of fused mateterial therein.

11. An apparatus of the character described comprising a receptacle for holding fused metalliferous material, a conduit combined with receptacle and adapted to contain fused material, means for maintaining a vacuum in the conduit 'to cause the metalliferous material to rise therein and the contained metal to volatilize 12. An apparatus for the electrolytic reduction and distillation of metals, comprising a tank for holding fused metalliferous materials, a conduit combined with the tank and adapted to contain fused material,` means for controlling the temperature of the fused material in the conduit, and a condenser for metallic vapor connected to the conduit and means for maintaining a ucts of the yelectrol sis in vapor form and 15 vacuumv in the conduit to canse fused mate'- rialto rise therein and the contained metal- .i

i to volatilize.

AI3., In combination with a furnace" for Volatilizing metal, a condenser, a mold ad- 'jacent thereto, means'y or conducting the metal from the condenser to the mold and means for preventing contact of the air with. the metal.

14, .A process for the production of metals, comprisingelectrolyzing a molten bath containing v a compound of the metal desired, and WithdraWingy the metaiiic produt arpressure less t an atmospheric.'

15. A process for making magnesium, comprising electrolyzing a magnesium salt at a temperature of at least. 650 C.,` approximately, and under a pressure lowenough to permit vaporization of the magnesium produced, withdrawing' the magnesium vapor apart from the anodic products of thc electrolysis, and condensing the magnesium vapor so withdrawn.

In testimony whereof I aix my signature.

HERMAN E. BAKKEN. 

